MAGNETIC SENSING DEVICE AND ELECTRONIC COMPASS USING THE SAME
First Claim
1. A magnetic sensing device comprising:
- a magnetic sensor for detecting magnetism;
bias-magnetic-field generating means for applying bias magnetic fields having opposite polarities to each other to the magnetic sensor;
detecting means for detecting output voltages that are obtained in response to the bias magnetic fields having the corresponding polarities;
calculating means for determining a difference between the output voltages that are obtained in response to the bias magnetic fields having the corresponding polarities; and
control means for controlling the bias-magnetic-field generating means so that the difference becomes substantially zero.
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Abstract
Positive and negative bias magnetic fields are applied to a sensor unit 12 to determine first and second output voltages. A first difference between the first and second output voltages is calculated. Next, correction bias magnetic fields, each of which is obtained by adding an additional bias magnetic field to a corresponding one of the positive and negative bias magnetic fields, are applied to the sensor unit 12 to determine first and second output voltages. A second difference between the first and second output voltages is calculated. Then, the first difference is compared with the second difference. When the first difference is larger than the second difference, the magnitude of the additional bias magnetic field is increased to minimize the difference, i.e., to made the difference substantially zero.
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Citations
10 Claims
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1. A magnetic sensing device comprising:
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a magnetic sensor for detecting magnetism; bias-magnetic-field generating means for applying bias magnetic fields having opposite polarities to each other to the magnetic sensor; detecting means for detecting output voltages that are obtained in response to the bias magnetic fields having the corresponding polarities; calculating means for determining a difference between the output voltages that are obtained in response to the bias magnetic fields having the corresponding polarities; and control means for controlling the bias-magnetic-field generating means so that the difference becomes substantially zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification